The present invention relates to a hinge of an infant support apparatus, and to infant support equipment, or apparatus, such as a stroller, buggy or high chair, for example, includes a hinge.
Strollers and buggies and other infant equipment are generally provided with a frame or other structural components which are joined together by a hinge to allow the equipment to be collapsed to a folded condition and expanded to an unfolded, or operative, condition.
It is often desirable to enable connecting structural members of the apparatus to pivot through more than 90 degrees about a pivotal axis of a hinge and preferably close to 180 degrees, so that the apparatus can be fully collapsed to occupy a minimal amount of space.
There is a requirement to provide a hinge which prevents the trapping of fingers in the hinge mechanism. It will be appreciated that due to lever action, the forces generated by a person collapsing and unfolding an apparatus are greatly increased at or close to the hinge and therefore severe injury may occur, particularly to fingers.
Typically, more dangerous hinges comprise two hinge members which can be pivoted between a straight condition and a bent condition, such that during pivoting in one direction an opening is formed between the hinge members which is subsequently closed during pivoting in an opposing direction causing trapping of fingers and injury. It is an object of the present invention to provide a hinge which reduces the risk and ideally does not cause such an injury.
A number of earlier hinges will now be described in more detail to aid understanding of the improvements made by the present invention.
FIG. 7 shows a prior art hinge 120 connecting two structural members of an infant support apparatus. The hinge is configured so that the structural members are aligned when the hinge is in a straight condition. That is, the longitudinal axes of the support members are generally aligned when the hinge is straight and the structural members are positioned on opposite sides of the hinge. A hinge which aligns structural members in this way is referred to as an in-line hinge.
The hinge comprises two hinge members 122, 124 which together form a barrel shaped hinge having two generally circular parts which rotate relative to each other. Circular parts 126 of one hinge member 122 are located on both sides of a circular part 128 of the other hinge member 124. The circular parts are free to move relative to each other to allow pivotal movement. The circular configuration of the relatively moveable parts prevents the formation of a pinch point, or finger trap, since a gap does not open between the hinge members during pivotal movement. However, in order to allow the structural members to be pivotal through 180 degrees, the pivot axis must be off-set sufficiently from the longitudinal axes of the structural members, otherwise the structural members contact each other prior to pivotal movement through 180 degrees e.g. at about 150 degrees or less.
Accordingly, the requirements of the hinge shown in FIG. 7 is that the hinge ends are both circular to prevent trapping and that the pivot axis is off set. As will be seen, satisfying both of these requirements results in a relatively large and bulbous hinge.
Another prior art hinge 130 is shown in FIG. 8, which also comprises barrel shaped hinge members 132, 134 but in this arrangement even though the pivotal axis P is aligned with the longitudinal axis of one structural member 136, in order to allow pivotal movement through 180 degrees the structural members 136, 138 are off-set from one another. Therefore, a pinch point is avoided in this example because of the barrel configuration and the hinge appears slightly less bulbous, but the design results in an off-set hinge, which may cause some bending or shear when the longitudinal forces applied to the hinge are resolved.
In this arrangement, pivotal movement beyond the straight condition of the hinge is prevented by contact between the hinge member 134 and the hinge member 132 on the outside of the hinge.
FIG. 9 shows another prior art hinge 140, which is designed to prevent over-rotation of the hinge beyond a straight condition, although in the configuration shown, the hinge cannot pivot through more than about 120-150 degrees.
The hinge 140 comprises hinge members 142, 144 having complementary circular parts 146, 148 which can slide relative to each other to allow pivotal movement. The part 148 has a longitudinal extension 150 which is adapted to abut against a surface 152 of part 148 to prevent pivotal movement beyond the straight condition. However, if a finger were to be accidentally located between external surfaces 154, 156 when the hinge is closed, injury would be incurred because of the lever action which magnifies the closing force.